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Inside the hottest place on Earth

Erta Ale, the most active volcano in Ethiopia, is located in the Afar Region

Earth scientist Dr Dougal Jerram, from Durham University, joined a BBC team to investigate the geology of the Danakil desert in northern Ethiopia - officially the hottest place on Earth. Here is his account of mapping an active volcano from inside the crater.

Like a true journey to the centre of the Earth, volcanoes provide a unique window into our planet's interior.

They provide a direct means by which our Earth cools itself, form a vital link with the developing atmosphere and can be an awesome yet terrible hazard to the people and animals that live around them.

But just how do we get into the guts of a volcano?

This is exactly what I set out to do as part of a scientific expedition into the Danakil desert.

As part of a team headed by Kate Humble, with vet Steve Leonard, medic Mukal Agarwal and biologist Richard Wiese, and a full expedition crew, we explored the region's legendary Afar tribes people, saw how the animals and man live in the extreme environment and came face to face with one of the Earth's most geologically active areas.

Feeling the heat

To get "up close and personal" with the active volcanic environment in the Danakil, I used 3D technology from the University of Durham's structural and visualisation facility, to provide a high resolution 3D map of the inside of a volcano.

This 3D technology uses millions of laser points reflected off surfaces to map out features of interest, providing a virtual 3D reconstruction of the environment surrounding the scan site, with a resolution down to millimetres.

The team was able to test the equipment at the Dabbahu fissure

The only problem was how to get the laser scanner into the volcano to capture this real life snapshot of such an active and dangerous phenomena.

On the way to the volcano we encountered the harsh living conditions in the Afar at first hand as we followed the old routes into the Danakil desert, where the active volcanoes are located.

The geology team had two main objectives: to test the equipment's portability through a camel train to image a giant volcanic crack - the Dabbahu fissure.

The other goal was to get down into Erte Ale, one of the oldest lava lakes on the planet.

The Dabbahu fissure opened overnight in 2005, where the ground literally tore itself apart as part of a much larger process which is happening as the Horn of Africa rips away from the main African continent, forming the Great African Rift system.

It is very rare to witness such a fissure forming event, pretty much as it happens and the team was keen to get the scanning equipment to the fissure to record this geological wonder before it erodes and becomes just another scar on the landscape.

This part of the expedition was almost thwarted by the difficulty of getting the equipment to the fissure and the fact that dangerous gases are still emanating from it.

'Gateway to hell'

With only 12 hours at the fissure, geologist Steve Smith and I managed to get three scans of the fissure completed and provide a vital test of the equipment before embarking on the main part of the expedition - to scale Erte Ale and provide the first laser scan of one of the oldest lava lakes on the planet.

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Dougal Jerram abseils down into the Erte Ale volcano

The scanning equipment weighed some 80kg and, for the most part, was being transported to the experiment sites by camel - a fitting mode of transport for such state-of-the-art kit.

Now the team needed to get the kit and the scanning team down into the heart of Erte Ale and get a scan from within the crater itself.

Standing at the lip of the lava lake you can see why the locals see this as "the gateway to hell", as the incandescent bubbling lava lake hisses like some badly burned porridge cauldron, overturning and occasionally belching molten lava.

This was to be a major technological feat, as well as a science first.

The kit, myself and Steve, plus camera man and climbing expert all needed to get down into the volcano, set up the final laser scan and get out in one piece.

It was a precision job, like landing on the Moon, as the team lowered into Erte Ale and recorded the first ever 3D laser scan of this remarkable volcano.

The laser scanning technology enabled us to investigate the natural environment in a completely new light by bringing the outcrop with its inaccessible cliffs, volcanic fissures and lava lakes into the computer where it could be analysed.

Such data provides the high resolution details from which we can see how the Earth's structures have formed, measures the exact size and shape of the volcano and provides a vital snapshot of the Earth's active and sometimes violent volcanic system in action.

The Hottest Place On Earth: episode one on Thursday 19 March on BBC One at 2100 GMT and episode two on Thursday 26 March at 2100 GMT

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